1. Field of the Invention
The present invention relates to a film information obtaining apparatus, and more particularly to a film information obtaining apparatus having a photometric unit for metering a predetermined range larger than an image recordable region of a photographic film to detect and obtain various information items from the photographic film.
2. Description of Related Art
A film printer for exposing images recorded on a photographic film, such as a negative film, to a light-sensitive material, such as photographic paper, must detect information including the type of the photographic film, the size of the image frame (for example, the conventional size (having an aspect ratio of 2:3)/panorama size/high-vision size) and so on, the quantity of characteristic of the image (for example, the density and color tone) which must be exposed, so as to determine an exposing condition of the image. When the image is exposed, the image must be brought to a predetermined exposing position. To bring the image to the exposing position, a movement state of the photographic film and the like must be detected. In addition, the position of an image recorded on the photographic film must be detected.
Also an image processing apparatus for reading an image recorded on a photographic film by a scanner to record the thus obtained image onto a recording medium or to display the image on a display unit must detect various information items from the photographic film. Accordingly, a structure has generally been employed in which photosensors corresponding to various information items to be obtained, or to be detected are provided to detect the various information items in accordance with the data outputted from each of the photosensors.
That is, for example, a DX code is read by a DX code detecting sensor, the contents of the DX code are determined in accordance with the data outputted from the foregoing sensor so as to detect the type of the film, the light transmissivity of a region in which the edge of the image frame exists is detected by a frame detecting sensor, and the position of the image frame and the size of the frame are detected in accordance with the data outputted from the sensor. Moreover, the photographic film is moved in such a manner that the image frame is brought to the exposing position, and the mask and the exposure factor are controlled. In addition, the image brought to the exposing position is metered by a photometric sensor, the exposing condition is determined in accordance with the image data obtained by the photometric operation and the image frame brought to the exposing position is printed to a photographic paper.
However, the fact that the above-mentioned structure requires a multiplicity of photosensors has a problem in that the cost of the apparatus cannot be reduced.
Another structure is known in which one of sensors is commonly used, the data outputted from the common sensor is temporarily sorted in a common memory and information which is included in various information items to be detected and which has been obtained from the common sensor is subjected to an analysis, so that the corresponding data only is selectively extracted from the data stored in the common memory to detect it.
For example, a DX code detecting sensor and a frame detecting sensor are formed into a common sensor and a line sensor for dividing one line into tens of pixels to meter one line is provided so that the data outputted from the line sensor is stored in the common memory. Only the data corresponding to the region, in which the DX code on the photographic film has been recorded, is extracted from the common memory, and the contents of the extracted data are analyzed so that the type of the film is detected. Then, only the data corresponding to the region, in which the edge of the image frame of the photographic film exists, is extracted from the common memory to analyze the contents of the extracted data so that the position of the image frame and the size of the frame are detected.
However, the foregoing structure has a problem in that all data items outputted from the common sensor are stored in the common memory and the data stored in the common memory includes a large quantity of data which is not required to detect each information. That is, the process of selectively extracting only the data corresponding to information, which must be detected, from the common memory (in other words, a process for determining the address of a region, in which the data corresponding to information which must be detected is stored, and extracting the data stored in the region having the determined address) becomes too complicated. Thus, there arises a problem in that excessively long time is required to a complete detection of all of various information items which must be detected.
In view of the foregoing problem of the large cost, it might be considered feasible to employ a structure in which a single photosensor (for example, a line sensor or an area sensor) having a multiplicity of light receiving elements divides substantially the overall surface of the photographic film including spaces outside the image recording regions into a plurality of pixels for metering the same, and detecting the above-mentioned various information items in response to the signals outputted from the photosensor.
Since the photographic film has perforations formed on the two sides in the widthwise direction thereof (and sometimes cut portions, such as notches), an incidental light beam allowed to pass through the perforation or the notch has a largest light quantity among light beams made incident from various positions of the photographic film. Therefore, the photometric condition of the photosensor must be adjusted to prevent saturation of the output from the photosensor and the output from a signal processing circuit disposed next to the photosensor even if the light beam allowed to pass through the perforation or the like is made incidenton thephotosensor. However, the quantity of the light beam allowed to pass through the image recording region of the photographic film is smaller than the above-mentioned maximum quantity of light for at least a quantity corresponding to the base density of the photographic film. Therefore, the above-mentioned adjustment of the photometric condition raises a problem in that the dynamic range permitted for the photometric process with respect to the image is reduced (the ratio of the highest level of a photometric signal and the lowest level of the same is lowered).
A structure of a scanner provided for the above-mentioned image processing apparatus or the like for the purpose of accurately reading an image recorded on a photographic film has been known, in which the photometric condition (for example, charge storage period of the image photometric sensor and the quantity of stop which is adjusted by a stop provided on the light incidental side of the photosensor) is changed depending on whether the photographic film is a negative film or a positive film, so as to adjust the dynamic range for the photometric process with respect to the image on the film for each of the photographic films such tat the dynamic range becomes maximum. However, even a scanner of this type also requires photosensors exclusively for detecting information other than information of the image itself apart from the foregoing photometric sensor.
A technique is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 63-189850, in which the dynamic range is changed between an operation for reading an image on a photographic film and an operation for detecting the edge of the image. However, the above-mentioned technique has not contrivance for detecting information also from a region of the photographic film in which a perforation or notch is formed by using a photometric sensor for metering an image.